A. Field of the Invention
This invention relates generally to printing devices, and more particularly to hand-held labelers wherein the position of a label-containing web must be accurately determined, and wherein the position-determining mechanism must be accurately adjusted to compensate for manufacturing and other tolerances.
B. Prior Art in the United States
Hand-held labelers utilizing thermographic printing devices are known. Examples of such handheld labelers are illustrated in U.S. Pat. No. 4,264,396 to Stewart, U.S. Pat. No. 4,407,692 to Torbeck and U.S. patent application Ser. No. 485,012 filed Apr. 14, 1983. Mechanical hand-held labelers utilizing position adjusting devices are also known, an example of such a labeling machine being disclosed in U.S. Pat. No. 4,207,131.
While the devices disclosed in the above-described references do provide a way to make imprints on a thermosensitive web, they do not contain certain of the features provided by the device of the present invention. For example, when printing with a thermal printing device, particularly with a high density printing device such as one of the devices illustrated in the aforementioned U.S. Pat. No. 4,407,692 and application Ser. No. 485,012, it is necessary accurately to control the timing of the energization of the various ous printing elements as a function of the position of the web. For example, in such a system, the web is continously fed, and the appropriate printing elements must be energized at the precise time that the portion of the web on which the imprinting is desired is positioned adjacent the printing head. The problem of head control is further compounded by the fact that each of the printing elements has a length and a width of only a few mils. As a result, the position of the web must be precisely controlled to avoid printing gaps and changes in print density, and a mechanism must be provided to adjust the position of the labels relative to the printing head to compensate for manufacturing and other tolerance.